Design and Optimization of a Slotless PMSM with Hexagon Distributed FPCB Winding

In this paper, the winding loss problem and optimization method of flexible printed circuit board (FPCB) hexagonal slotless permanent magnet synchronous motor (PMSM) are studied. Due to the particularity of the motor winding structure, the existing direct winding calculation method is difficult to apply to the hexagonal winding structure, the general multi-objective optimization design method based on 3D finite element method (FEM) is often time-consuming and difficult to implement. In order to solve the above problems, firstly, the effects of pole-slot matching and stator-rotor parameters on electromagnetic performance is analyzed. The propose analytical models for winding eddy current loss, circulating current loss, and electromagnetic torque are established and validated using 3D FEM and experiments. Then, in the optimization of winding connection mode, the winding loss of different connection modes is calculated, and the connection mode with the smallest loss is selected as the optimal scheme. Finally, the fitting function is established for the winding copper loss analysis model as the optimization objective function, the NSGA-II multi-objective optimization algorithm and TOPSIS comprehensive decision are used to optimize the winding shape with the best performance of this motor.